What needs to be done prior to surveying the hoistway?

Before surveying the hoistway, it is essential to install a plumb line. This tool allows for accurate vertical alignment and measurement, which is crucial in the surveying process. It helps ensure that any structures or installations are perfectly vertical, providing a reference point for subsequent work. By using a plumb line, surveyors can determine if the hoistway is plumb and assess any necessary adjustments, which is critical for the safe and effective installation of elevators or other systems related to the hoistway.

The other options serve different safety and functionality purposes but are not specifically required before surveying the hoistway itself. Safety nets, warning signs, and fire extinguishers contribute to workplace safety but do not play a direct role in obtaining accurate measurements or alignment, which is the primary reason for installing the plumb line first.